Phthalocyanines are known pigments having many applications, such as colorants for inks and coatings and even for turfgrass paints. It is generally known to color turf. U.S. Pat. No. 5,747,419 describes the use of iron containing dyes. Many turf colorants were in the marketplace, though most pigments used were proprietary. See, e.g., J. Van Dam and K. Kurtz, “A Turfgrass Colorant Study,” published in the Summer 1971 edition of California Turfgrass Culture, where a variety of proprietary blends were tested, including Stayzgreen™, Greenstuff™, Greenzit™, Sta-Green™, Everbright™, and others. Most colorants are green and blue, and a high percentage of them are used for cosmetic greening golf courses. Using a green indicator to spray the course with pesticides accentuates the green grass, making it look robust and healthy. DE 2,511,077, which published in 1976, claimed a method for coloring a lawn using a phthalocyanine dye. Label information states that the Regreen™ turf colorant available from Precision Laboratories contains a copper phthalocyanine pigment.
Copper phthalocyanine has been used in combination with monoalkyl esters of phosphorous acid, or salts thereof, either with or without mancozeb. U.S. Pat. No. 5,643,852 describes a method of enhancing turf quality in turfgrass by applying in specific ratios certain phthalocyanines in combination with (i) phosphorous acid or an alkaline earth metal salt thereof or certain monoester salts of phosphorous acid and (ii) certain ethylene bisdithiocarbamate contact fungicides. U.S. Pat. No. 5,336,661 discloses using on turfgrass formulations comprising 1 part of certain monoester salts of phosphorous acid, for example fosetyl-Al (preferably Aliette™) and 1.5 to 2.5 parts of mancozeb (preferably FORE™). The FORE™ brand of mancozeb contains 70% mancozeb and 1-2% of copper phthalocyanato(2-). See http://www2.siri.org/msds/f2/bzz/bzzsc.html, for ingredients in Rohm and Haas Co.'s FORE™ FUNGICIDE, 62440.
Of particular interest is U.S. Pat. No. 5,599,804 which describes a method of combating fungi and enhancing turf quality in turfgrass by applying in specific ratios, in particular between 0.01 and 0.1 parts of phthalocyanines (in particular pigment Blue 15) in combination with one part of phosphorous acid or an alkaline earth metal salt thereof or with certain monoester salts of phosphorous acid. The examples in U.S. Pat. No. 5,599,804 do not tell how much of the pigment blue was present, but we believe the amount was about 0.03 to 0.04 parts of pigment Blue 15 per part of fosetyl-Al.
The commercial product is believed to contain only about 4% of phthalocyanine compound, and it seems that this phthalocyanine compound is pigment Blue 15. In tests of this product, the color was found to be not natural appearing, and short-lasting. By short-lasting with normal weather the color is visibly depleted in a week and very faded in two to three weeks.
We have found that turfgrass treated with a commercial formulation above and with formulations such as described in U.S. Pat. No. 5,599,804 do not provide turfgrass that is natural looking. Further, the color dissipates in about a week, which is substantially shorter than the interval at which turfgrass is to be treated with the fungicide. However, there are a number of reasons why no manufacturer has made a product having more phthalocyanine dye. First, custom dictates that the fosetyl-Al product be provided at a concentration of about 70% by weight, and it is generally thought that the surfactants and dispersants needed to formulate this fosetyl-Al with even 4% of phthalocyanine dye does not leave much weight available for the formulation. Second, at amounts above 0.1 parts phthalocyanine dye, at the recommended dosage of fosetyl-Al, a formulation containing most phthalocyanine dyes is unacceptably phytotoxic. Indeed, at the recommended dosage of fosetyl-Al, a formulation containing even 0.1 parts of the preferred pigment Blue 15 of U.S. Pat. No. 5,599,804 is unacceptably phytotoxic.